Apparatus and method for a bioptic real time video system

ABSTRACT

A method and apparatus of displaying an electronic video image using a head-worn near-to-eye display in a non-immersive fashion, such that the wearer can choose, through simple adjustments of their neck and eye angles, to either look at the displayed video image or their natural environment. The invention also relates to the incorporation of prescription lenses into the optical chain of the near-to-eye display. The invention also relates to the use of motion and position sensors incorporated into the head-worn device to enable automatic stabilization of the video image. The invention also relates to the use of motion and position sensors incorporated into the head-worn device to automatically adjust the vertical angle of either the camera or the electronic display or both, by sensing the vertical angular position of the user&#39;s head.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of and claims priority to U.S. patentapplication Ser. No. 13/309,717 filed Dec. 2, 2011, which claimspriority to and the benefit of U.S. Provisional Patent Application Ser.No. 61/419,539 filed Dec. 3, 2010, the entire contents of which areincorporated herein by reference.

FIELD OF THE INVENTION

The invention relates generally to the field of wearable electronicdisplays and more specifically to the field of vision care.

BACKGROUND

There are numerous applications for lightweight head-worn near-to-eyedisplays. These are commonly called Head Mounted Displays (HMD). HMDsdisplay to the eye an electronically rendered image such that the wearerperceives that they are watching a sizeable electronic display at somedistance in front of them. The applications that use such HMDs arenumerous, including but not limited to virtual reality, electronicgaming, simulation environments such as for military simulations orflight simulators, medical applications such as for the enhancement ofsight, and consumer applications such as the ability to view videos in amobile setting.

One of the fundamental challenges of HMDs is the tradeoff between thedisplay's Field of View (FOV), being the size of the virtual display asperceived by the wearer, and pixel size. FOV is normally defined as thenumber of angular degrees subtended within the viewer's overall field ofvision, horizontally, vertically, or on the diagonal. Horizontal FOVdimensions in the range of 20-30 degrees are typical, with largerdimensions being possible at significant expense. Pixel size issimilarly expressed as the number of angular arc minutes ( 1/60th of adegree) subtended by a single, typically square pixel element. As onemight expect, to achieve a larger FOV with a given pixel resolution(number of pixels), results in a larger pixel size, and consequent lossof image detail.

Peripheral vision is that portion of the human field of vision outsidethe center, say, 10-15 degrees FOV. Peripheral vision is extremelyimportant in some HMD applications, especially those in which the wearermust maintain a connection with their natural environment tocontextualize their situation, and enable way finding, orientation, andmobility. To provide significant peripheral vision via the electronicdisplay requires an extremely large (and expensive) HMD. AlternatelyHMDs which provide a significant natural peripheral vision external tothe HMD housing, provide a very limited virtual electronic FOV.

Many HMD applications can benefit from the incorporation of a livecamera into the HMD, such that the wearer can not only view electronicdata from a source, such as a video file, but also live video images ofthe world in front of them. Image processing can be used to enhance thelive camera image before it is presented to the eye, providingmagnification, enhancement of brightness, or improved contrast forexample.

In HMD systems that are to be used for multiple activities, differentcamera angles may be required for different tasks. For example, toobserve an object a distance, the camera angle should be nearlyhorizontal relative to the horizon when the wearer's neck is straightand their gaze angled at the horizon. On the other hand, to viewhand-held objects at a close distance requires a camera that is angleddownward, in order to avoid a highly exaggerated downward neck posture.In this manner, the angle of the camera mimics the angular movement ofone's eyes in a non-HMD world.

Finally, the angle of the display relative to the eyes is also dependenton the specific tasks of the wearer. In certain situations the wearerwould like to look into the electronic display only temporarily, and bylooking up at an angle higher than their habitual gaze. In othersituations, the wearer would prefer a more immersive usage model, wherethe electronic display is directly in front of their normal line ofgaze.

What is needed then is a general HMD device that is capable of providingsignificant unobstructed peripheral vision outside of the electronicdisplay FOV, while simultaneously providing a high resolution videoimage. Further, the ability to adjust the angle of the display and thecamera according to the wearer's specific activity would providesignificant comfort and increased usability.

Other aspects and features of the present invention will become apparentto those ordinarily skilled in the art upon review of the followingdescription of specific embodiments of the invention in conjunction withthe accompanying figures.

SUMMARY

The ability to quickly alternate as required by the specific task,between viewing an image presented in the electronic display and viewingthe world without the electronic display, enables many possible usagemodels for an HMD. Furthermore, in an HMD with an integrated camera, theability to adjust the vertical camera angle for different tasks, viewingobjects distant and close for example, significantly increases theusability of such a device. Finally, an HMD whereby the user is able toselect the vertical position of the electronic display, in order totradeoff a comfortable immersive video experience versus maintaining abroad natural field of view enables the HMD to be used in a variety ofuser applications and postures.

The invention, in one aspect, relates to a method of orienting anelectronic near-to-eye display such that the wearer views it slightlyabove their habitual line of sight for a given task. In this manner thewearer, through slight neck and eye angle adjustments can, with minimaleffort, alternate between the electronic display and their naturalvision.

In one embodiment, the electronic display is mounted slightly above thewearer's habitual line of sight, so that by angling the neck slightlyforward and directing their gaze slightly upward, they can look into thedisplay. Alternately by angling the neck slightly back and directingtheir gaze slightly down, they can view below the electronic displayusing their natural vision.

In another embodiment, the apparatus incorporates the wearer'sprescription ophthalmic lenses, so that whether they gaze up into theelectronic HMD or down using their natural vision, they are able to doso through their prescription lenses. This embodiment of the inventionalleviates the need to switch between the HMD device and the wearer'shabitual spectacles.

In another embodiment the apparatus incorporates a video camera, whichprovides the video information to the electronic display, the angle ofthe camera being adjustable as required by the specific task.

In any of the above embodiments the source of the video may come from adevice other than the camera, in any standard electronic video formatsuch as MPEG for example.

In another embodiment the apparatus may deploy motion sensing componentsin order to facilitate image stabilization for the electronic videoimage that is captured by the camera.

In another embodiment the motion sensing components could be used todetermine the angular orientation of the apparatus, so that the verticalcamera angle can be automatically adjusted based on head position.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is pointed out with particularity in the appended claims.The advantages of the invention described above, together with furtheradvantages, may be better understood by referring to the followingdescription taken in conjunction with the accompanying drawings. In thedrawings, like reference characters generally refer to the same partsthroughout the different views. The drawings are not necessarily toscale, emphasis instead generally being placed upon illustrating theprinciples of the invention.

FIGS. 1 through 4 are highly schematic diagrams of an embodiment of thesystem of the invention;

FIG. 5 is a more detailed view of an embodiment of the system forautomatically adjusting the angle of the camera.

FIG. 6 is a more realistic rendering of a particular embodiment of thesystem of the invention.

FIGS. 7A through 7C depict three successive frames of simulated video,in order to show how motion vectors can be used for image stabilization.

FIGS. 8A and 8B show an alternate method of altering the camera anglethrough defining a window on the image sensor rather than by physicallyaltering the camera angle.

DETAILED DESCRIPTION

In brief overview and referring to FIG. 1 and FIG. 6, the system in oneembodiment includes prescription lenses 6 mounted to an eyeglasses frame1. The Head Mounted Display portion of the system comprises a housing 2,which can move relative to the eyeglasses frame 1, about a pivot point3. The HMD housing 2 incorporates HMD optics 5, a camera 9, and HMDelectronics 8 (collectively, the “HMD”).

In the orientation depicted in FIG. 1, the wearer's head/neck posture isangled slightly back 4, and he is viewing the world 7 through theprescription lens 6, without the use of the HMD optics 5 or camera 9.

In FIG. 2, the head/neck angle 4 is slightly forward, allowing the userto view the HMD optics 5 through the same prescription lens 6 bydirecting their gaze at a slight upward angle 7. In this mode, videoinformation viewed through the HMD optics 5 can be provided from thevideo camera 9, oriented at an outward angle 10 such that objects at adistance can be viewed in the video image. As discussed, the video couldalso come from other sources.

In FIG. 3 the head/neck angle 4 is unchanged from FIG. 2, but the camerahas been angled downward on a pivot point 11 so that the camera angle 10is now aimed at a nearby object close at hand, perhaps in the wearer'shands.

In FIG. 4 the slightly forward head/neck angle 4 remains unchanged, butthe HMD angle has been significantly lowered by pivoting the HMD housing2 relative to the eyeglasses frame 1, around a pivot point 3. In thisorientation the wearer is able to adopt a more comfortable viewing angle7 for near-in tasks. Furthermore, the camera angle 10 can be directedfurther downward because the camera pivot point 11 moves with the HMDhousing 2.

In FIG. 5, a method is shown whereby a linear motor 12 can be used toadjust the vertical angle 10 of the camera 9. The camera rotated arounda pivot point 11 that is affixed to the HMD housing 2. With theadjustment of the camera angle automated thus, it is possible to usemotion and position sensors embodied in the HMD electronics 8, toprovide positional data that can be used to control the linear motor 12.

Alternately, the angle 10 of the camera 9 can be adjusted manually bythe user.

FIG. 7 shows how the same motion and position sensors embodied in theHMD electronics 8 can be used to enable an image stabilization function.FIGS. 7A, 7B, and 7C show three consecutive frames of video as capturedby the camera 9. Because of the normal movement of the wearer's head,successive frames of video have a translational (up/down, left/right)and rotational (angular) position relative to the previous frame. Theframe depicted in FIG. 7B for example has shifted to the right/down androtated slightly counter-clockwise relative to the previous frame 7A.The translational vector Δ1 and rotational angle θ1 can be determinedfrom the motion and position sensors embodied in the HMD electronics 8.By applying the opposite of the translational vector and the reverserotational angle to the pixels in the video frame 7B, the differencesbetween the two frames 7A and 7B can be removed. FIG. 7C carries theexample further, showing a frame of video that is now shifted left/downand clockwise relative to the previous frame 7B. A new vector Δ2 androtational angle θ2 can be applied, and so forth so that over time,small frame-to-frame variations caused by the wearer's head movement areremoved from the displayed video. To distinguish between minor headmovements, for which image stabilization should be applied, and grosshead movements, which indicate the wearer's scene of interest haschanged, requires that the image stabilization function only be appliedto small translational and rotational vectors.

In FIGS. 8A and 8B, the angle of the camera 9 is adjusted not byphysically rotating the camera as previously discussed. Rather, an areaof pixels, or a window 13, 14 can be defined on the image sensor so thatthe wearer perceives that the camera angle is physically altered. Thistechnique requires a camera system wherein the usable image sensor areais larger than the video that is to be displayed to the wearer. Motionand position sensors embodied in the HMD electronics 8 can be used todetermine the wearer's head/neck angle 4 and, based on this information,define a capture window 13, 14 that gives the wearer the perception of ahigh or low camera angle 10.

While the present invention has been described in terms of certainexemplary preferred embodiments, it will be readily understood andappreciated by one of ordinary skill in the art that it is not solimited, and that many additions, deletions and modifications to thepreferred embodiments may be made within the scope of the invention ashereinafter claimed. Accordingly, the scope of the invention is limitedonly by the scope of the appended claims.

What is claimed is:
 1. A head-worn device comprising: a frame; abinocular electronic near-to-eye display assembly pivotally attached tothe frame; and a camera with vertical angle adjustment forming part ofthe electronic near-to-eye display; whereby the wearer views theirenvironment directly with their head in a first position such that theelectronic near-to-eye display is pivoted upwards; views a video imagepresented on the electronic near-to-eye display with their head in asecond position such that the electronic near-to-eye display is pivoteddown in front of their eyes; and views the video image generated fromthe camera and presented on the electronic near-to-eye display withtheir head in a third position, wherein the third position is such thatthe electronic near-to-eye display is pivoted further down in front ofthem than when their head was in the second position.
 2. The head-worndevice according to claim 1, wherein the vertical angle of the camerachanges between a first angle and a second angle when the wearer's headis in the second and third positions respectively.
 3. The head-worndevice according to claim 1, wherein the electronic near-to-eye displayautomatically pivots into the different positions based upon the user'shead being in the first, second, and third positions.
 4. The head-worndevice according to claim 1, wherein the electronic near-to-eye displayis manually pivoted into the different positions when the user's head isin the first, second, and third positions; and the vertical angle of thecamera automatically changes between a first angle and a second anglewhen the wearer's head is in the second and third positionsrespectively.
 5. The head-worn device according to claim 1, wherein theelectronic near-to-eye display is manually pivoted into the differentpositions when the user's head is in the first, second, and thirdpositions; and the vertical angle of the camera is manually adjustablebetween a first angle and a second angle when the wearer's head is inthe second and third positions respectively.
 6. The head-worn deviceaccording to claim 1, wherein the vertical angle of the camera adjustsaccording to whether the user's head is in the first position or thesecond position.
 7. The head-worn device according to claim 1, furthercomprising: an orientation sensor; and a motion sensor, wherein thevideo image from at least one of the camera and display electronics isstabilized using motion information provided by the orientation andmotion sensors.
 8. The head-worn device according to claim 7, whereinthe vertical angle of the camera is automatically adjusted for a giventask using information provided by the orientation and motion sensors.9. The head-worn device according to claim 7, wherein the perceivedvertical angle of the camera is determined not by adjusting the physicalangle of the camera but by defining an area of pixels of the camerasensor presented to the user upon the electronic near-to-eye display.10. The head-worn device according to claim 7, wherein the electronicnear-to-eye display displays either an image acquired by the camera oran image coupled to the electronic near-to-eye display from anotherimage source.
 11. A head mounted electronic near-to-eye display module,the electronic near-to-eye display module comprising: a cameraadjustably attached to the display module; a display electronics circuitin communication with the camera; a head mounted display optics having afirst surface adjacent the display electronics circuit and a secondsurface disposed towards a user's head; and a means for pivotallyattaching the electronic near-to-eye display module to a frame worn bythe user, whereby the wearer views their environment directly with theirhead in a first position such that the electronic near-to-eye displaymodule is pivoted upwards; views a video image presented on theelectronic near-to-eye display module with their head in a secondposition such that the electronic near-to-eye display module is pivoteddown in front of their eyes; and views the video image generated fromthe camera and presented on the electronic near-to-eye display modulewith their head in a third position, wherein the third position is suchthat the electronic near-to-eye display module is pivoted further downin front of them than when their head was in the second position. 12.The head mounted electronic near-to-eye display module according toclaim 11, wherein the vertical angle of the camera changes between afirst angle and a second angle when the wearer's head is in the secondand third positions respectively.
 13. The head mounted electronicnear-to-eye display module according to claim 11, wherein the electronicnear-to-eye display automatically pivots into the different positionsbased upon the user's head being in the first, second, and thirdpositions.
 14. The head mounted electronic near-to-eye display moduleaccording to claim 11, wherein the electronic near-to-eye display ismanually pivoted into the different positions when the user's head is inthe first, second, and third positions; and the vertical angle of thecamera automatically changes between a first angle and a second anglewhen the wearer's head is in the second and third positionsrespectively.
 15. The head mounted electronic near-to-eye display moduleaccording to claim 11, wherein the electronic near-to-eye display ismanually pivoted into the different positions when the user's head is inthe first, second, and third positions; and the vertical angle of thecamera is manually adjustable between a first angle and a second anglewhen the wearer's head is in the second and third positionsrespectively.
 16. The head mounted electronic near-to-eye display moduleaccording to claim 11, wherein the vertical angle of the camera adjustsaccording to whether the user's head is in the first position or thesecond position.
 17. The head mounted electronic near-to-eye displaymodule according to claim 11, further comprising; an orientation sensor;and a motion sensor, wherein the video image from at least one of thecamera and display electronics is stabilized using motion informationprovided by the orientation and motion sensors.
 18. The head mountedelectronic near-to-eye display module according to claim 17, wherein thevertical angle of the camera is automatically adjusted for a given taskusing information provided by the orientation and motion sensors. 19.The head mounted electronic near-to-eye display module according toclaim 17, wherein the perceived vertical angle of the camera isdetermined not by adjusting the physical angle of the camera but bydefining an area of pixels of the camera sensor presented to the userupon the electronic near-to-eye display.
 20. The head mounted electronicnear-to-eye display module according to claim 17, wherein the electronicnear-to-eye display displays either an image acquired by the camera oran image coupled to the electronic near-to-eye display from anotherimage source.